Keywords:

biomass;

carbon dioxide;

catalysis;

cellulose;

switchable solvents

MCC Hammer: Microcrystalline cellulose (MCC) is dissolved and subsequently regenerated in a CO2-based switchable solvent system, drastically reducing its crystallinity index and thereby its recalcitrance to hydrolysis. Among the investigated systems, based on cheap, widely available chemicals, is one capable of dissolving up to 15 wt % MCC within 1 h at room temperature. Break it down!